Wasn't Vendetta programmed by the Protheans to say what it did?
At least you admit no one, including the ME1 characters, did anything after the SR1 was destroyed to find a way to stop the reapers
It was programmed to react to certain events yes. Much like Alivina or what ever the VI on the Citadel was in the first game. How ever at the time of Reaper invasion Asari or any other species were not advanced enough to be able to program a base language. Not even counting the fact that language changes over the years.
Ardat-Yakshi as good example said by Samra to be an old Asari dialect.
You keep hammering home that the ME1 characters didn't do anything. Yet you seem to miss the simple fact on your way to persecute them. The big important fact you keep overlooking is the fact that no one believed them. Even Shepard didn't get any support only Anderson and Hackett to a lesser extend believed him. How ever the 3 out of 4 councilors didn't believe him. And the remaining human parliament didn't believe him.
Your posts keep having this feel of you pointing at them demanding them to awnser for their inaction and how their inaction caused problems. But you seem to willingly ignore they didn't choose inaction. They simply couldn't act. Everything was swept under the rug leaving them with nothing to be able to do.
There is barely true proof of Protheans in the galaxy. A few odd ruins but about it. Any tech left over is extremely rare. Hence the high penalty for withholding it from the council as well as the security Anderson took when getting the beacon from Eden Prime. The reapers as the victor of the last cycle would leave nothing behind to show they exist. Their entire strategy is the sudden surprise of their existence. Cripple key points of government quickly before anyone can react then slowly harvest the rest while they are disorganized and unable to react in a unified way anymore.
Ane certainly nothing would be left that might show weaknesses or ways to defeat them. They weren't able to harvest so many cycles by being dumb idiots leaving the "how to destroy us" hand book on every planet.